No abstract

No abstract

Abstract. The present study aimed to evaluate the immune effect of intramuscular primary immunization by the nucleic acid vaccine pcDNA/glycerophosphodiester phosphodiesterase-interleukin-2 (pcDNA/Gpd-IL-2) and enhanced immunization 2 weeks later with the combination of mucosal adjuvant CpG-oligodeoxynucleotides (ODN) and Gpd-IL-2 recombinant protein on skin infection caused by Treponema pallidum (Tp) in New Zealand rabbits. At week 8 following immunization, MTT assay was used to detect spleen cell proliferation, while enzyme-linked immunosorbent assay was performed to detect the cytokine and secretory immunoglobulin A (SIgA) levels. At week 10 after primary immunization, rabbits were inoculated with 10 5 Tp (Nichols strain). Alterations in the skin redness, swelling and ulceration were recorded for 0-60 days. In addition, positive rate of Tp in skin lesions and ulcer formation rate were examined using dark field and silver staining. The results indicated that intramuscular primary immunization by nucleic acid vaccine pcDNA/Gpd-IL-2 followed by enhanced immunization via nasal feeding with mucosal adjuvant CpG-ODN and Gpd-IL-2 recombinant protein induced the higher levels of Tp Gpd specific antibodies, increased the secretion of IL-2 and interferon-γ, and promoted the proliferation of T cells in the first 8 weeks after immunization. Furthermore, this immunization strategy stimulated the production of mucosa specific SIgA antibody. Thus, this strategy led to the lowest Tp positive and ulcer formation rates at the Tp infection sites, as well as healing of skin lesions on the earliest time point (day 42). In conclusion, immunization by nucleic acid vaccine pcDNA/Gpd-IL-2 followed by enhanced immunization with a combination of mucosal adjuvant CpG-ODN and Gpd-IL-2 recombinant protein is an effective immune strategy to induce strong mucosal immune responses and immune protective effects.

The aim of the present study was to evaluate the diagnostic value of the Treponema pallidum (Tp) antigen Tp0693 for syphilis. ELISA was used to examine the serum levels of Tp0693. The sample-to-cutoff ratio (S/CO) value was used to generate a receiver operating characteristic (ROC) curve. A correlation analysis was performed to compare the detection efficacy of Tp0693-specific ELISA, Treponema pallidum Particle Agglutination (TPPA), Tolulized Red Unheated Serum test (TRUST) and LiZhu™ Tp-ELISA. The area under the ROC curve was 0.99, indicating good diagnostic efficacy. When the diagnostic specificity reached 100%, the diagnostic sensitivity was up to 93.5%. Tp0693-specific ELISA results were not correlated with those of TPPA, TRUST and LiZhu™ Tp-ELISA (correlation coefficient, 0.122, 0.114 and 0.025, respectively). The latent syphilis rate was highest (12%, 9/75) for all syphilis specimens with a S/CO in the grey area. In conclusion, for syphilis specimens with a S/CO in the grey area, TPPA should be used for further confirmation of the diagnosis. Tp0693 may be used as a diagnostic antigen for syphilis; however, further study regarding its potential use is required.

Radon is the main background source of dark matter and neutrino experiments. Radon concentration (mBq/m3) measurement by liquid scintillation detector is a highly sensitive method at low temperatures using silicon photomultipliers (SiPMs) arrays. The SiPM performance characteristics are closely related to the lower detection limit of the detector. In this study, we built an automatic and accurate low-temperature measurement system to study the single photoelectron (SPE) spectrum, SPE resolution, optical crosstalk, and after-pulse of the SiPM at different temperatures. As a result, we obtained the variation trend of the SiPM parameters at different temperatures, and the SiPM optimal working conditions were obtained, which can improve the detector's sensitivity.